Percussion drill



Oct. 22, 1940. c. J. ENDSLEY PERCUSSION DRILL Filed March 5. 1957 v 2 Sheets-Sheet l INVENTOR: C'OLSO/V J ENDSLEX BY A TTORNE Y.

Oct. 22, 1940. c ENDSLEY 2,218,528

PERCUSSION DRILL Filed March 5, 1937 2 Sheets-Sheet 2 I A HID- INVENTOR.

60 5 ON J ENDSLZY BY I QUW' ATTORNEY.

Patented Oct. 22, 1940 UNITED STATES PATENT OFFICE 2,218,525

PERCUSSION DRILL Colsdn J. Endsley, Los Angeles, Calif. Application March 5, 1937, Serial No. 129,225

'7 Claims.

The present invention relates to improvements in percussion drills and refers particularly to a rotary device for operating such drills.

The device to which the present improvements 5 pertain is fully described in Patent No. 1,995,504

issued to me on March 26, 1935. This patent covers a rotary device provided with a series of balanced hammers, and the improvements herein described are directedto means for making the 10 operation of such device more convenient and effective.

To this end, it is an object of the invention to provide a more positive means for stopping the hammers Which. have been set in motion upon 15 striking the drill. A further object is the provision of means foradjusting the device to varibodying the invention. Fig. 2 is a fragmentary View illustrating on a larger scale some of the more important parts of the invention, Fig. 1.

Fig. 3 is an end elevation, parts of Fig. 1, sub- 3 stantially in agreement therewith, and-Fig. 4 is a side elevation of portions of the device,.illustrating parts which could not conveniently be shown in Fig. 1 without obscuring other important features of the invention.

5 The structure of the invention in the preferred form shown in the drawings comprises a post I, which for convenience is shown set on abase 2. A bracket 3 is mounted to slide axially on the post, and it is held in adjusted position by means 40 of a set screw 4. A rail 5 is pivotally secured to this bracket, at 6, and it is shaped to support a slidable member 1', provided with a boss 8, which forms a bearing for a drive shaft 9, which in turn is adapted to support the main rotating frame l0 45 of the invention. This frame is star-shaped and is fitted at the points pivotally to support pairs of balanced hammers l I. From this, it is seen that the frame ii! is mounted to rotate on the shaft 9 to slide longitudinally. A sprocket I5 is fastened to the drive shaft 9 and a chain 16 connects this 55 sprocket with the second sprocket ll of a spindle I ous angles or inclination.

1 It is often desirable to mount a. drill verticall and it is convenient for this purpose to provide a l8, which is mounted to rotate on the sleeve I3. A worm I9 is secured to this spindle and positioned to rotate a wheel 20, which in turn is perforated to ride on a squared portion of the drill l4. From this it is seen that rotation of the 5 drive shaft 9 communicates rotation to the drill.

A second bracket 2| is adjustably mounted on the post I and held in position by means of a set screw 26. The upper end of this bracket is perforated to receive a pin 22 which rides in a slot 23 of the rail. This combination makes it possible to adjust the bracket 3 on the post relative to the bracket 2| in order to change the angular relation of the rail to the post and thereby to permit the operator toadjust the drill to varisleeve, similar to the sleeve l3, for guiding the drill in this position or, if preferred, it is possible to make the sleeve I3 detachable from the bracket 7 12, as indicated by means of the clamping bolt 25. The sleeve may then be detached and mounted on the bracket H, in the position indicatedin dotted outline in Fig. 1, whereupon the 25 chain l6, which preferably has been detached during this operation, may again. be mounted on the wheel l1.

In the manner substantially as above described, it is possible to direct a drill to suit operating conditions.

In the patent above referred to, resilient means were provided for stopping the rotation of the hammers, caused by impact against the drill, and While such m-eans appeared quite satisfactory, experience has taught me that positive devices for stopping the hammer rotations are much to be preferred; Such means is, in Fig. 2, shown to comprise an annular member secured to the hub ll or handles ll of the hammers H in any suitable manner, as by welding the members to the hammer handles. Diametrically opposed stops 42 and 43 are mounted within this member and these stops normally take a position perpendicular to the radial center line of the frame arm 4|. A yoke shaped member 44 is mounted to straddle the end of each arm 4| and this member is fitted pivotally to support pawls 45 and 46 which, by means of suitable springs 47 and 48, are normally held engagingthe stops 42 and 43. To this end it is, of course, necessary to shape the stops to project sidewise sufiiciently to engage the ends of the pawls. On the slide 1 is mounted a projection'ifi, positioned in the path of travel of a bell crank 49, which in turn is pivotally secured to the arm 41, there being one bell crank on each arm. Sliding bars 5! and 51 are pivotally secured to the outer extremities of this bell crank, and they normally extend to a point near the inner end of the 'pawls t5 and 46. This position is indicated on the arm at the left side of Fig. 2. As the frame it commences to rotate, it is seen that the bell crank 39 of this arm strikes the projection 56, causing the bell crank to tilt and to push the sliding bar 59 forward, thereby to withdraw the pawl 45 from the stop 43. This position is indicated at the top of Fig. 2, but it is important to remember that this position is attained while the arm is in its lowermost position. The perforations 5th, ti at the inner end of the bars 50, 5i are, in Fig. 2, shown transversely elongated in order to afford the studs 49 of the bell cranks d9, freedom to swing from normal into tilted position.

Continued rotation of the frame causes the hammer it to strike the drill is and, as the pawl 45 has been withdrawn from the stop 53, it is seen that the hammer is free to yield, causing the sidewise projection of the stop 23 to strike the upper end of the sliding bar 5% and to force this down into its original position. Release of the pawl 55 is thereby effected and its spring 4? is permitted to push the pawl back into the path of the stop d3. From this, it is seen, that nearly one-half of a revolution is allowed in which to reset the pawl it. If the projection 56 were placed at the top instead of at the bottom the pawl would have to act so quickly that it might not return in time to catch the stop.

While, in the patent above referred to, the revolving frame was operated by a hand crank, I prefer in this case to perform the operation by means of a wheel 59, as indicated in Figs. 3 and 4. One reason for this is that a hand wheel may be found. more convenient to operate, but the employment of such operating wheel has an other advantage, which now will be described. In Fig. 3, I have shown an annular member, or tire Bi, of the same diameter as the wheel 6t and fitted with an extension 62, which is shaped to engage periphery of the annular members 40. In order to mount this tire, it is required to move the hammers into the position shown in Fig. 4 and to unscrew the nuts $3. The projection, 62, of the tire, is bifurcated to straddle the bolt of this nut, which latter thereupon is remounted to lock the tire in position. When this tire is mounted on the revolving frame, it is seen that two wheels are provided, on which the device of the invention may be perambulated upon lifting the lower end of the post off the ground and using it as a tongue by means of which to propel and steer the vehicle in this manner provided, substantially as indicated in 3.

When the hammers rebound, they develop considerable speed, causing the stops within the annular members ifi to strike the stop pawls with so much force that the repeated hammering may damage the parts. In order to cushion these blows, I have made the yoke members as slidable on the ends of the frame arms. A spring 65 maintains each member advanced against stops 66. As the pawls 45, it are mounted on this yoke member, it is seen that the latter is able to yield against the tension of the spring and thereby to absorb the shock of the hammer impact.

As stated, means is provided for advancing the hammer frame relative to the advance movement of the drill. The mechanism illustrated for this purpose is, for the sake of simplicity, shown to comprise a hand lever I0, fitted with a pawl H, riding in teeth 12 of the slide 1. As the hand lever is pivotally fixed on the rail 5, it is seen that a slight elevation of this lever suffices to advance the slide. A stop 13 may be provided, against which the lever, dropping by gravity, may be arrested.

As shown in the drawings, the device is set to drill left-handed, the operating wheel being on the right side of the post. It may, however, frequently be required to drill right-handed, and this may readily be prepared for in the following manner. The slide 1 is first pushed forward, past the pivotal point 22, whereupon the bolt at 6 is removed. It is now noticed that the bracket 2| is. divided at the top to provide a vertical pivot 21, on which the rail 5 can be given a one-half turn, whereupon it again is clamped in position. It is then only required to swing the bracket l2 in the opposite direction and to readjust the sleeve l3, and the device is ready for right-hand operation.

The structure herein described is merely illustrative of my invention and may be modified to the extent covered by the appended claims.

I claim:

1. In a percussion drill, a post, a star-shaped frame mounted for rotation on said post, balanced pairs of hammers mounted for rotation on the points of said frame, a drill supported by said post in the path of travel of said hammers, stops mounted to rotate with the hammers, means on said frame normally engaging said stops to maintain the hammers non-rotatable in a predetermined fixed position, and means on said post p0- sitioned to actuate said stop engaging means successively to release said hammers before reaching said drill, the rebound of the hammers upon striking the drill resetting said stop engaging means.

2. In a percussion drill, a support, a member pivotally mounted on one side of said support, a series 'of balanced pairs of hammers pivotally mounted on said member, a drill longitudinally slidable on said support in the path of travel of said hammers, means for rotating said member to cause the hammers to strike said drill, and means for shifting the member tothe opposite side of said support.

3. In a percussion drill, a post, a bracket pivotally mounted on said post, a star-shaped memb-er pivotally mounted on said bracket, a plurality of balanced hammers mounted to rotate at the points of said member, a hand wheel on the pivot of the member for rotating said member, the diameter of said wheel being greater than the outside diameter of said member, and an annular member of the same diameter as the said wheel attachable to said member, the wheel and the said annular member combining to form two wheels upon which to roll the device along the ground.

i. In a percussion drill, a post, a rail on said post and inclineable relative to the post, a member longitudinally slidable on said rail, a drill slidable in said member, a star-shaped frame mounted to rotate on said member, balanced hammers pivotally mounted at the points of said frame for striking said drill, said hammers being free to rebound upon striking the drill thereby to rotate said hammers, and means for positively arresting the hammers in striking position.

5. In a percussion drill, a rotatable frame, a series of striking devices mounted on said frame in normal balance, each device comprising a pair of hammers on the ends of a common handle pivotally mounted on the frame midway between the for releasing each pair of hammers for recoil rotation before one of the hammers strikes, said means actuated by the hammers upon recoil r0- ta'tion thereof to actuate the pawl withdrawal means to release the pawls to again lock the hammers in striking position.

6. .In a percussion drill, a post, a support vertically adjustable on said post, a member slidable on said support, a drill support on said member, a frame mounted for rotation on said member, a series of pairs of balanced hammers pivotally mounted on said frame to strike a drill in said drill support when the frame is rotated, means normally maintaining said hammers non-rotatable in striking position, and means actuating said hammer maintaining means for releasing the hammers for rotating before reaching striking position, said releasing means'being reset upon rotation of the hammers again positively to lock the hammers in striking position.

7. Ina percussion drill, a support adjustable to various angles of inclination, a slide on said support, a drill holder mounted on said slide, a frame rotatably fixed on the slide, hammers pivotally mounted on said frame in balanced pairs, means normally locking each pair of hammers in position for one hammer to strike a drill in saidholder when the frame is rotated, means for releasing each pair for recoil rotation before striking, means actuated by frame rotations gradually to advance the drill in the holder, and manual means for advancing said slide to readjust the position of the advanced drill relative to the hammers.

COLSON J. ENDSLEY. 

